GE AZ45E07DA Series Technical Service Manual page 11

AZ6500
When an AZ6500 Zoneline is in the heating mode,
the resistance heater or the compressor runs with
the appropriate fans. The control is capable of
independently switching power for two resistance
heater loads. Each of the two heater loads can
be made up of di erent heating elements, but the
elements will be tied together in parallel. There
are three stages of operation associated with the
heating mode:
• Stage 1: Heating due to heat pump (compressor)
with both fans on.
• Stage 2: Heating due to heat pump (compressor)
and supplemental 1000 watt resistance heater
(Heater A) with both fans on. (This mode can also
be activated via Aux Set mode to run in place of
stage 1 heating). This auxiliary setting is known
as Boost Heat, and essentially disables Stage
1 heating which is replaced by Stage 2 heating.
When this mode is active, it will run when the
Zoneline is being controlled via the Zoneline
control panel or when a remote wall thermostat
is connected and calling for heat pump. It will
override Stage 1 heating in both cases. NOTE:
Any time the Zoneline enters Stage 2 heating
mode, it should continue heating in this mode
until the room temperature is satis ed. If the
room o set increases, then Stage 3 heating will
be engaged.
• Stage 3: Heating due to resistance heater
(Heater A, B and C) - indoor fan only on.
NOTE: Any time the Zoneline enters Stage 3 heating
mode, it will continue heating in this mode until the
room temperature is satis ed, regardless of indoor
room temperature o set or outdoor temperature
conditions. The Zoneline can then resume normal
heating operation modes of Stage 1 or Stage 2
heating upon the next call for heat.
NOTE: In low fan speed, the Zoneline will only
activate heater A and B to allow for a maximum
heater output of 3800 watts. A, B, and C output is
only available in high speed. Heat Pump Mode and
Heater B ill never be on at the same time
Upon initial start-up or resumption after a power
interruption, Stage 3 (Heater A and Heater B) are
energized at full power to generate heat until the
room temperature rises to the temperature setting
regardless of the outdoor temperature.
Automatic changeover between the compressor
and the heating elements is utilized.
In order to keep the compressor from stalling out
when trying to start against the high side refrigerant
pressure, the control circuit has a built-in automatic
time delay to allow the internal pressure to
equalize. The control circuit will not try to start the
compressor until it has been o for three minutes.
To minimize compressor cycling, the control has
a built-in minimum compressor run time of three
minutes (+/- 10 seconds). Even if the thermostat is
satis ed, or the indoor temperature is dropping, the
compressor will run for a minimum of three minutes.
The Zoneline can switch to Stage 2 heating, but
must wait until the 3 minutes of compressor run
time is satis ed before switching to Stage 3 heating.
• 1st STAGE HEAT (HEAT PUMP ONLY)
Once heating initializes, the room temperature
will start to rise. The compressor will run
until the temperature rises 0.9°F above the
temperature control set point, at which time
the compressor will shut down. If the outdoor
ambient temperature is < 25°F, Stage 1 heating
will be disabled and only Stage 3 heating will
energize. This is also the case for the remote
wall thermostat. When the outdoor ambient
temperature is > 46°F, the Zoneline runs at First
Stage (Heat Pump).
• 2nd STAGE HEAT (HEAT PUMP + HEAT A) - Boost
Heat mode
When either the room temperature falls from
the setting by greater than 1.8°F or the outdoor
temperature is lower than 25°F, Stage 2 heating
will be disabled and only Stage 3 heating will
energize.
If the outdoor temperature is above 25°F the
control will energize Stage 2 heating. Stage 2
heating will continue to operate until the room
temperature exceeds the temperature control
set point by 0.9°F, at which time the heater and
compressor will stop.
NOTE: The second stage heat is not utilized in class
2 mode. Unless Aux Set "boost heat" is selected.
Stage 2 heating will operate when the thermostat
calls for Stage 1 heating.
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